Composition in tablet form for determining alkaline content by titration



was July 23; 1929.

UNITED STATES PATENT GFFME.

JOHN H. BUCHANAN, AMES, IOWA, ASSIGNOR TO AMERICAN BOTTLEBS OF (BBO- NATE'D BEVERAGES, OF WASHINGTON, DISTRICT OF COLUMBIA, A CORPORATION.

OOH'POBITION IN TABLET FORM FOR DETERMTNING ALKALINE CONTENT BY TITRATION.

Io Drawing.

equivalent to one per cent by weig t of sod1um hydroixide (caustic) and is compressed into tablets.

The grainage of the tablets is so standardized that the average tablet is equivalent to ten cubic centimeters of twenty-five hundredths normal alkali. This would represent one per cent of alkali calculated as sodium hydroxide.

. The approximate alkaline strength of a ten cubic centimeter volume of the alkaline solution to be tested, may then be determined by the addition of the tablets. Since each tablet represents one per cent, i. e., contains exactly the correct amount of acid to neutral ize an alkaline content of one per cent, the number of tablets required to neutralize the full. alkaline content of the solution is an ap-' proximate index of the percentage of actual alkali in the solution when calculated as sodium hydroxide.

While other acids can be used, it was found that potassium bisulfate is particularly adaptable to the test. The results are more definite if the acidsubstance 'elds a strong 5 acidinwater. Potassium bis fate yields sulfuric acid (H SO which is a very stron acid. Weak acids would not do as the en point would not be very definite. Also, tassium bisulfate exists as a solid, and he- 40 cause of which it is possible to repare it in such form that it may be molded into tablets by machine operation. Other satisfactory acids would, in all probability, be liquids.

Alkaline solutions, especially the solutions used for washin beverage and milk bottles, are usually go w or brown and get very dirty from a accumulation of foreign substances. It is therefore necessary touse an indicator with suflicient difference between its neutral colorand end point, and usual color of the solutions being tested, to make the ch in color easily discernable.

It is also necessary to use an indicator that willwork in the presence of strong alkalies ratio of one hal ounce to five Application filed March 20, 1926. Serlalllo. 96,320.

as well as weak. That is, it must indicate not only the presence of caustic, but also the presence of carbonates. It thereby gives total alkalinity, a feature which has been lacking in the kinds of tests previously devised.

The indicator tetra bromo phenol sulfon phthalein serves these purposes. Its color range is in the proper (H) -ion concentration range, and is very definite, because the yellow color usually found in the alkaline washing solution does not interfere. In other words, it gives in the solution for which it is particularly adaptable, a sharp endpoint.

The indicator brom phenol-b ue (tetra brbmo phenol sulfon phthalein) finely powdered is added to the preparation potassium bisulfate to the extent of one tenth of one 'per' cent.

Ethyl alcohol is used to moisten nation.

Five per cent of talc-is added'to remove moisture.

White oil (1i uid paraflin) is added in the unds of prepared substalnce. This is fozllimegpur o'se of reventin cog an sti int ema- Ehine in vhich i dgablets are prepared.

As previously stated, the grainag'e of the tablets is so standardized that the everagetablet is e uivalent to ten cubic centimeters of the combitwentyve hundredthsnormal alkali, or its equivalent one per cent of alkali calculated as a 5 sodium hydroxide. p v

The purpose of brom phenol blue indicator is to show when the reaction of neutralization between the acid substance of the tablet and alkali of the washing solution is '05 foruseofthetablets 1s as follows. Ten cubic centimeters of com letedi e rocedure recommended t e solution to be tested are accurately measured and transferred to a clear glass tumbler. One tablet is added and dissolved in the solution. If the solution remains blue. it is evident that the strength in terms of alkali, calculated as sodium hydroxide, is greater than one per cent. If the solution turns yellow it is evident that the strength is less than one per cent. By addition of tablets until the yellow color is obtained the approximate strength of the solution is determined because of the fact that the total number of tablets necessary to cause the yellow color is numerically the same as the proportion of alkaline content bears to the whole solution in terms of percentage. That is, each tablet added until the'yellow color is obtained represents a strength of one per cent of alkali calculated as sodium hydroxide.

The reaction illustrating the action of the potassium bisulfate is shown 2KHSO =K SO +H SO The reaction shows that sulphuric acid is developed which will furnish the acid properties to such a solution. Such a tablet when dissolved in water would give an acid reaction to the water and consequently would neutralize the alkali.

While the composition has been described herein in detail for use-in titrating' a quantity of ten cubic centimeters of alkaline solution, it is to .be understood that the grainage of the tablets may be so varied so as to be used in titrating greater or lesser quantities of alkaline solution without departing from the spirit of the invention or the scope of the subjoined claims. I

Having described my invention, I claim:

1. A composition in tablet form comprising potassium bisulfate as the acid constituent, with an indicator, of such standardized grainage and proportions that each tablet is equivalent to a predetermined pro ortion by weight of sodium hydroxide (caustic) for the purpose of determining by titration the alkaline content of any solution. 2. A composition in tablet form comprisingpotassium bisulfate as the acid constitutent, with tetra bromo phenol sulfron phthalein as the indicator, of such standardized grainage and proportions that each tablet is equivalent to a predetermined proportion by! weight of sodium hydroxide (caustic) for the purpose of determinin by titration the alkaline content of any solution.

3. A composition in tablet form comprising potassium bisulfate as the acid constituent, with an indicator, of such standardized grainage and proportions that each tablet is equivalent to ten cubic centimeters of twentyfive hundredths normal alkali, for the purpose of determining the alkaline content of any solution by titration.

4. A composition" in tablet form comprising potassium bisulfate as the acid constituout, with tetra bromo phenol sulfon phthalein as the indicator,ofsuch standardized grainage and proportions that each tablet is equivalent to ten cubic centimeters of twenty-five hundredths normal alkali for the purpose of determining the alkaline content of any solution by titration.

5. A titration tablet comprising potassium bisulfate and a filler, of such standardized grainage and proportions that for titration purposes each tablet is equivalent to a fractional part of one percent of alkali in solution, said percentage being Within the range of and including one tenth to one-half of one percent.

6. A titration tablet comprising potassium bisulfatc and a filler, of such standardized grainage and proportions that for titration purposes each tablet is equivalent to a specified percentage of alkali in solution, said percentage being wthin the range of and including one-tenth percent to five percent.

73A- tablet consisting of potassium bisulfate and a filler, of such standardized grainage and proportions that each tablet is equivalent to ten cubic centimeters of twentyfive hundredths normal alkali, for the purpose of determining by titration the alkaline content of any solution.

8. A composition comprising potassium bisulfate as the acid constituent with an indicator, of such standardized grainage and proportions that for titration purposes it is equivalent to a predetermined proportion by weight of sodium hydroxide (caustic).

9. A composition comprising potassium b1- sulfate as the acid constituent, with tetra bromo henol sulfon phthalein as the indicator, 0 such standardized grainage and proportions that for titration purposes it 1s equivalent to a predetermined proportion by weight of sodium hydroxide (caustic).

10. A composition of matter for forming titration tablets, comprising otassium bisulfate, an indicator, talc, and w its oil, substantially as set forth.

11. A composition of matter for formlng titration tablets, comprising potassium bisulfate, tetra bromo phenol sulfon phthalein, talc, and white .011, substantially as set forth.

12. A composition of matter for forming titration tablets, comprising otassium bisulfate, tetra bromo sulfon p thalein, and a filler, substantially as set forth.

13. A composition of matter for forming titration tablets, comprisng potassium bisulfate, an indicator, and a filler, as set forth.

14. A composition of matter for forming tit-ration tablets, comprising 1 part potassium bisulfate, 1/1000 part tetra bromo phenol sulfon phthalein, 1/20 part talc, and 1/171'part white oil (liquid paralfin), substantially as set forth.

15. A process for determining the alkaline substantially 7 content of any solution whichconsists of rendering visible the alkaline or acid condition of the solution and measuring the alkaline content thereof by means of tablets consisting of potassium bisulfate and tetra bromo phenol solfon phthalein, each tablet being of such standardized grainage and proportions that it is equivalent to ten cubic centimeters of twenty-five hundredths normal alkali.

16. A process for determining the alkaline content of any solution which consists of rendering visible the alkaline or acid condition of the solution and measuring the alkaline content thereof by means of tablets consisting of potassium bisulfate and an indicator, each tablet being of such standardized grainage and proportions that it is equivalent to ten cubic centimeters of twenty-five hundredths normal alkali.

17. A process for determining the alkaline content of any solution which consists of rendering visible the alkaline or acid condition of the solution and measuring the alkaline content thereof by means of tablets consisting of potassium bisulfate and tetra bromo phenol sulfon phthalein, each tablet being of such standardized grainage and proportions that it is equivalent to a predetermined proportion by weight of sodium hydroxide (caustic).

18. A process for determining the alkaline content of any solution which consists of rendering visible the alkaline or acid condition of the solution and measuring the alkaline content thereof by means of tablets consisting of potassium bisulfate and an indicator, each tablet being of such standardized grainage and proportions that it is equivalent to a predetermined proportion by weight of sodium hydroxide (caustic).

19. A process for determining the alkaline content of any solution which consists of neudering visible the alkaline or acid condition of the solution by means of an indicator, and measuring the alkaline content thereof by means of tablets of potassium bisulfate, each tablet being of such standardized grainage and proportions that it is equivalent to ten cubic centimeters of twenty-five hundredths normal alkali.

20. A process for determining the alkaline content of any solution which consists of rendering visible the alkaline or acid condition of the solution by means of an indicator, and measuring the alkaline content thereof by means of tablets of potassium bisulfate, each tablet being of such standardized grainage and proportions that it is equivalent to a predetermined proportion by weight of sodium hydroxide (caustic).

21. A process for determining the alkaline content of any solution which consists of rendering visible the alkaline or acid condition of the solution by means of tetra bromo phenol sulfon phthalein, and measuring the alkaline content thereof by means of tablets of potassium bisulfate, each tablet being of such standardized grainage and proportions that it is equivalent to ten cubic centimeters of twenty-five hundredths normal alkali.

22. A process for determining the alkaline content of any solution which consists of rendering visible the alkaline or acid condition of the solution by means of tetra bromo phenol sulfon phthalein, and measuring the alkaline content thereof by means of tablets of potassium, bisulfate, each tablet being of such standardized grainage and proportions that it is equivalent to a predetermined proportion by weight of sodium hydroxide (caustic).

' JOHN H. BUCHANAN. 

